/*
 *  linux/kernel/vsprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
/*
 * Wirzenius wrote this portably, Torvalds fucked it up :-)
 */

#include <stdarg.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>

unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base) {
    unsigned long result = 0, value;

    if (!base) {
        base = 10;
        if (*cp == '0') {
            base = 8;
            cp++;
            if ((*cp == 'x') && isxdigit((int)cp[1])) {
                cp++;
                base = 16;
            }
        }
    }
    while (isxdigit((int)*cp) && (value = isdigit((int)*cp) ? *cp - '0' : (islower((int)*cp) ? toupper(*cp) : *cp) - 'A' + 10) < base) {
        result = result * base + value;
        cp++;
    }
    if (endp)
        *endp = (char *)cp;
    return result;
}

/* we use this so that we can do without the ctype library */
#define is_digit(c) ((c) >= '0' && (c) <= '9')

static int skip_atoi(const char **s) {
    int i = 0;

    while (is_digit(**s))
        i = i * 10 + *((*s)++) - '0';
    return i;
}

#define ZEROPAD         1  /* pad with zero */
#define SIGN            2  /* unsigned/signed long */
#define PLUS            4  /* show plus */
#define SPACE           8  /* space if plus */
#define LEFT            16 /* left justified */
#define SPECIAL         32 /* 0x */
#define SMALL           64 /* use 'abcdef' instead of 'ABCDEF' */

#define do_div(n, base) ({ \
int __res; \
__asm__("divl %4":"=a" (n),"=d" (__res):"0" (n),"1" (0),"r" (base)); \
__res; })

static char *number(char *str, int num, int base, int size, int precision, int type) {
    char c, sign, tmp[36];
    const char *digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    int i;

    if (type & SMALL)
        digits = "0123456789abcdefghijklmnopqrstuvwxyz";
    if (type & LEFT)
        type &= ~ZEROPAD;
    if (base < 2 || base > 36)
        return 0;
    c = (type & ZEROPAD) ? '0' : ' ';
    if (type & SIGN && num < 0) {
        sign = '-';
        num = -num;
    } else
        sign = (type & PLUS) ? '+' : ((type & SPACE) ? ' ' : 0);
    if (sign)
        size--;
    if (type & SPECIAL) {
        if (base == 16)
            size -= 2;
        else if (base == 8)
            size--;
    }
    i = 0;
    if (num == 0)
        tmp[i++] = '0';
    else
        while (num != 0)
            tmp[i++] = digits[do_div(num, base)];
    if (i > precision)
        precision = i;
    size -= precision;
    if (!(type & (ZEROPAD + LEFT)))
        while (size-- > 0)
            *str++ = ' ';
    if (sign)
        *str++ = sign;
    if (type & SPECIAL) {
        if (base == 8)
            *str++ = '0';
        else if (base == 16) {
            *str++ = '0';
            *str++ = digits[33];
        }
    }
    if (!(type & LEFT))
        while (size-- > 0)
            *str++ = c;
    while (i < precision--)
        *str++ = '0';
    while (i-- > 0)
        *str++ = tmp[i];
    while (size-- > 0)
        *str++ = ' ';
    return str;
}

int vsprintf(char *buf, const char *fmt, va_list args) {
    int len;
    int i;
    char *str;
    char *s;
    int *ip;

    int flags;       /* flags to number() */

    int field_width; /* width of output field */
    int precision;   /* min. # of digits for integers; max
                number of chars for from string */
    int qualifier;   /* 'h', 'l', or 'L' for integer fields */

    for (str = buf; *fmt; ++fmt) {
        if (*fmt != '%') {
            *str++ = *fmt;
            continue;
        }

        /* process flags */
        flags = 0;
    repeat:
        ++fmt; /* this also skips first '%' */
        switch (*fmt) {
        case '-':
            flags |= LEFT;
            goto repeat;
        case '+':
            flags |= PLUS;
            goto repeat;
        case ' ':
            flags |= SPACE;
            goto repeat;
        case '#':
            flags |= SPECIAL;
            goto repeat;
        case '0':
            flags |= ZEROPAD;
            goto repeat;
        }

        /* get field width */
        field_width = -1;
        if (is_digit(*fmt))
            field_width = skip_atoi(&fmt);
        else if (*fmt == '*') {
            /* it's the next argument */
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        /* get the precision */
        precision = -1;
        if (*fmt == '.') {
            ++fmt;
            if (is_digit(*fmt))
                precision = skip_atoi(&fmt);
            else if (*fmt == '*') {
                /* it's the next argument */
                precision = va_arg(args, int);
            }
            if (precision < 0)
                precision = 0;
        }

        /* get the conversion qualifier */
        qualifier = -1;
        if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
            qualifier = *fmt;
            ++fmt;
        }
        qualifier = qualifier;

        switch (*fmt) {
        case 'c':
            if (!(flags & LEFT))
                while (--field_width > 0)
                    *str++ = ' ';
            *str++ = (unsigned char)va_arg(args, int);
            while (--field_width > 0)
                *str++ = ' ';
            break;

        case 's':
            s = va_arg(args, char *);
            if (!s)
                s = "<NULL>";
            len = strlen(s);
            if (precision < 0)
                precision = len;
            else if (len > precision)
                len = precision;

            if (!(flags & LEFT))
                while (len < field_width--)
                    *str++ = ' ';
            for (i = 0; i < len; ++i)
                *str++ = *s++;
            while (len < field_width--)
                *str++ = ' ';
            break;

        case 'o':
            str = number(str, va_arg(args, unsigned long), 8,
                         field_width, precision, flags);
            break;

        case 'p':
            if (field_width == -1) {
                field_width = 8;
                flags |= ZEROPAD;
            }
            str = number(str,
                         (unsigned long)va_arg(args, void *), 16,
                         field_width, precision, flags);
            break;

        case 'x':
            flags |= SMALL;
        case 'X':
            str = number(str, va_arg(args, unsigned long), 16,
                         field_width, precision, flags);
            break;

        case 'd':
        case 'i':
            flags |= SIGN;
        case 'u':
            str = number(str, va_arg(args, unsigned long), 10,
                         field_width, precision, flags);
            break;

        case 'n':
            ip = va_arg(args, int *);
            *ip = (str - buf);
            break;

        default:
            if (*fmt != '%')
                *str++ = '%';
            if (*fmt)
                *str++ = *fmt;
            else
                --fmt;
            break;
        }
    }
    *str = '\0';
    return str - buf;
}

int sprintf(char *buf, const char *fmt, ...) {
    va_list args;
    int i;

    va_start(args, fmt);
    i = vsprintf(buf, fmt, args);
    va_end(args);
    return i;
}
